Project Logs

Collapse

• Working on the project will begin

  Aleksejs • 06/21/2019 at 09:39 • 0 comments

  My work on this project is not fished. 

  I spent all-time for my degree work writing and a little bit project software part debugging. 

  But for now I officially have graduation as elektronical engeneer! YEAH I DID IT!!! 

  Now I have more time to spend for my projects! 

  And of course don't forget to comment ideas, work and options what is more or less needed. 

• Optical fiber cabel installation

  Aleksejs • 05/31/2019 at 16:48 • 0 comments

  As I'm at the telecommunication operator fiber optic technician I finally installed and fused to my apartments optical fiber cabel from outside ODF (optical distribution frame) with CATV analog and digital signals. 

  So the next step is to start testing/debugging and coding RF digital attenuator with RF Log detector. 

  But for now I must finish my bachelor degree paper works and print out the book for my graduation. 

• OpAmp MUX testing

  Aleksejs • 05/23/2019 at 23:03 • 0 comments

  Here is some testing report video of my automatically OpAmp gain switching depending on recieved laser signal with InGaAs photodiode. 

  Led switching indicate gain mux switching position. 

  On LCD display you can see sfp module TX power, InGaAs Photodiode RX power, sfp module temperature and voltage. And the last line indicate mux switching position number. 

  I2c driver little helped me with some different SFP modules:) 

• Photodiode MUX testing... and little fail

  Aleksejs • 05/19/2019 at 22:07 • 0 comments

  I'll begin from a little fail with photodiode Mux.

  At beginning of my PCB testing input block - pdotodiode input MUX I realized what I forgot to add mux switching pins and Logic high (+2.5v) pins for mux controlling:( That's was my second fail and next board hacking for adding this additions.

  Added two pin headers for Mux logic control and three pin header for logic control - Logic High.

  Mux switching tested by manually input switching between four inputs with Logic control inputs pins.

• SFP Testing

  Aleksejs • 05/19/2019 at 21:52 • 0 comments

  There are more SFP DDM libraries founded on the Internet for reading all necessary information from SFP modules.

  For now I get from SFP: TX bias current, TX power, RX power, module temperature, voltage, TX laser wavelength:

  On LCD display You can see:

  • SFP transceiver TX power values;
  • Photodiode RX power received from SFP module;
  • SFP module temperature;
  • SFP module voltage;
  • SFP module laser wavelength.

• SFP connecting

  Aleksejs • 05/14/2019 at 07:10 • 0 comments

  After hacking my board (after i make mistake with footprint It's soldering time... Part 3. Final step.) I started testing and modifying software writed by @oakkar7 (GitHub link) for my needs.

  At firs time I get almost all needed information from SFP module.

  This are: TX and RX power, temperature, voltage, transceiver wavelength, active link status.

  On the right upper corner located 100Mbp/s media converter (D-link DMS-920R) with TX 1310nm/ RX 1550nm. It's connected to the SFP, located on my device board. SFP with TX 1550nm/ RX 1310nm.

  Display currently shows information readed from SFP DDM interface (on this photo I didn't indicate SFP module wavelength).

  LED (on the left side) indicate SFP receiver status.

• It's soldering time... Part 3. Final step.

  Aleksejs • 05/13/2019 at 07:04 • 2 comments

  Looking back at my previous log (It's soldering time... Part 2. Step by step log.) You remember what I have some problem with wrong footprint? Yeahh :( 

  The solutions is my soldering skill testing :) But I just have some cheap chinese soldering iron with bold (2mm) tip. And part led pitch are 0.5mm. This is a real challenge to my skills.

  After hours of soldering finally I get this:

  Not so pretty as I would like, but there are no shorts and, I hope, it will work.

  Let's start testing ...

• It's soldering time... Part 2. Step by step log.

  Aleksejs • 05/09/2019 at 11:20 • 0 comments

  As the beginning of my Step-by-step log I'll show in pictures how goes my manual :))) Pick&Place machine :))) 

  And what goes wrong :(

  In It's soldering time... my step by step log. Part 1. I finished with removing remaining solder paste on stencil...

  1. Now it's time to show what's after accurate removing stencil from pcb:

  As You can see everything looks pretty nice! All footpads and especially small footpads with pitch from 0.65 to 0.45! are great covered with solder paste. I'm really happy with my first fork with stencil.

  2. It's time to turn ON my "Pick&Place machine" :) - my eyes, hands and tweezers :)))

  Every minute the number of components increased...

  And more increased....

  And until this step my happiness was no limit, until..... I unpacked next components to pace them....

  Ouuuuu..... :((((

  This wasn't what I expecting. 

  I several times change my component at schematic, but forgot to change also footprint.

  Conclusion:

  Don't forget, as I did, to double check, but better double-double check used and ordered parts in the project.

  
  

  To be continued....

• It's soldering time... my step by step log. Part 1.

  Aleksejs • 05/07/2019 at 09:09 • 0 comments

  This is first part of my soldering log.

  With starting of this project I also decide to try my first time soldering stencils (it is necessary to gain experience). As You saw before I already get my order with PCB's and stencil.

  For solder paste I ordered from Chip Quick "Thermally Stable Solder Paste No-Clean Sn63/Pb37 T4 (50g jar)" P/N:TS391AX50 with Revolutionary Formula: No Refrigeration Required! 

  Here preparing for soldering photo log with some comments:

  1. Unpacking stencil and preparing pcb:

  Stencil was packed two sides in hard board and the holes on both sides are sealed with a film so can't get there.

  2. I use same hard board and other pcb's for central board holding:

  This was same and my other project pcb's.

  3. Next is centring and fixing stencil:

  Stencil is placed and fixed. Get it correct only at second attempt. On the photo You can only see big alighting places, but trust my the smallest also are aligned :)

  4. Preparing and applying solder paste:

  Stencil fixed, solder paste ready for spread...

  5. Solder paste spreading:

  Paste spreading (I use some plastic card) from one side to other and back...

  6. Next need to clean out remaining paste:

  With same plastic card I clean put remaining solder paste...

  Conclusion:

  Working with stencil it's pretty simple steps, and where you need, depending on Your design component pitch and pin sizes, select right solder paste powder size and as hobbyist (my opinion) better select No-clean paste for fastest forking :)

  AND accurate align and fix stencil over the board, and after accurate removing stencil from the board.

  At my log Part 2 You'll see how goes my soldering, and what's was wrong with the plan :(

• PCB design and orderign

  Aleksejs • 04/30/2019 at 16:10 • 0 comments

  After spent time on PCB design, where I tried to combine different device nodes at the same time using this PCB as prototype board. On it I can control and read any devices module separately. All output and control pins traced to connector headers for future operations.

  So the device board spitted by the blocks: 

  • Photodiode MUX,
  • OPamp witch two muxes for variable gain control,
  • RF variable attenuation with RF Log detector,
  • ADC,
  • Three ports for SFP modules.

  Of course for ease soldering with PCBs I order stencil :)

  Next step will be.... 

  Yes! Soldering :)

View all 14 project logs